Niki Lauda believes Mercedes' feat of winning the first four races of the V6 era is a significantly more impressive achievement than Sebastian Vettel winning nine races in a row in 2013.

Vettel's 2013 season was the most comprehensive of his four world titles, with his incredible run at the end of the year only highlighting how comfortable Red Bull's advantage was. Mercedes has stolen a march on its rivals under the new regulations and Lauda insists the team deserves greater credit than Red Bull received in 2013 for what it is doing this season.

"This year we have new engines, new gearboxes, new electric brakes, and new cars," Lauda is quoted as saying by AUTOSPORT. "And the Mercedes cars finished the first four races, which for me is the outstanding result.

"If you have shitty engines like last year, and nine races in a row like Vettel, to finish all of them, this is easy. But to do the same now, with four races in a row, I think is an outstanding performance."

Lauda admits he has been taken aback slightly by how well Mercedes has done so far in 2014.

"I never expected it. For me, the most important thing is that we got the reliability going. We got everything together in a proper way. The others made it in the past, but never in the first year of completely new regulations."